I am a 22-year-old male physics graduate student who was diagnosed with a germinoma (brain tumor) and obstructive hydrocephalus in 8/2017. I went through three surgeries (releasing the excess fluid, biopsy, and shunt placement), followed by 4 21-day chemotherapy cycles, and then 20 sessions of proton radiation to the ventricles and tumor bed. I had a complete response after the second round of chemo, but I completed the whole treatment anyways as recommended by my oncologist. I finished my treatment regimen on 2/5/18.
I have now experienced three episodes in which, after a very short period of time, events which I perceive as real begin to feel like they were part of a dream instead. The first two times, on 2/15 (10 days after finishing radiation therapy) and 2/24, my perception of reality lasted a duration of 2 minutes; this third episode (which was Tuesday night, 3/6) I only know the past 30 seconds to be real, and the rest feels like a dream. The episodes seem to occur about once every ten days. Now six times while writing this e-mail, I doubted that I actually started it because of this experience. My dream/reality perception above is so far always accompanied by the physical feelings of (1) vertigo and (2) weightlessness when I move my head quickly. I first experienced the vertigo after my second week of radiation therapy, but it lasted for about one week without the aforementioned accompanying psychological side-effect. After my first two episodes of this symptom, the psychological effects disappeared after a good night's sleep. This time, however, the effect made me burst into tears. I am very afraid that it would be permanent and was emotionally overwhelmed.
I did not sleep particularly well that night. The "reality duration" extended from 30 seconds to about 10 minutes, but went away by noon today. For the first time I had this experience with no accompanying vertigo. The effect was lighter than it was last night.
I am frightened by this and don't know if it is going to get worse; other than this effect I am recovering well (I walk 2 miles/day, skip my midday nap, and some days I can read academic material for up to 5 hours without feeling tired). I am wondering if any of you have gone through this, experienced or heard of this bizarre side-effect?